Driveline component manufacturers, especially in the trucking industry, are continually being urged to improve the durability and reliability of driveline components, such as driveshafts, axles and gears. Since the best solution is not always merely one of "beefing up" the individual components, various damping devices have been conceived and are well-known in the art. Clutch damping/torque limiting devices are illustrated in U.S. Pat. Nos. 4,668,207, 4,693,354, 4,888,539, 4,947,972 and 5,009,301.
One problem of particular significance results when a truck driver overzealously engages the clutch by, for example, "side-stepping" the clutch. When a driver side-steps, the clutch pedal is depressed and a particular gear is selected. The engine is then revved up and the driver slides his foot sideways off of the clutch pedal, allowing the clutch pedal to snap back to the resting position. This results in a very rapid clutch engagement and application of torque to the driveline, inducing vibrations and oscillations into the driveline. The driveline components are seriously stressed and failure is hastened if the rate of torque application is faster than the natural frequency of the driveline. Specifically, unnecessary stress occurs when the driveline torque input has major harmonic content at frequencies at or above the lowest natural frequency of the driveline. Thus, if the rate of torque application is at or below the natural frequency, the driveline is not shocked.
It is therefore desirable to prevent overzealous engagement of a clutch by controlling the rate of torque applied to the driveline in a reliable, durable and cost-effective way.